When Israel tried earlier this week to assassinate a leader of the terrorist group Hamas, no less a friend of the Jewish state than President Bush protested. He wasn't saying that the helicopter attack in the Gaza Strip was aimed at an innocent - most assuredly it was not - but that such an attack threatened a new cycle of violence just as a comatose peace process was coming groggily to life.
No one - certainly not Mr. Bush - will take any satisfaction in the fact that his fears were borne out yesterday when a suicide bomber detonated an explosion on a Jerusalem bus, killing 16 people and wounding nearly 70.
Of course, to explain yesterday's horrifying act is not to justify it. But it was precisely the possibility of this sort of revenge that worried American officials who pressed Mr. Bush to issue a rare public condemnation of Israel on Tuesday after the attempted assassination of Hamas official Abdel Aziz Rantisi.
Predictably, yesterday's suicide bombing impelled Israel to counter-retaliate with another helicopter attack, this one deadly to two Hamas figures and several others. Now it will be even more difficult for Palestinian Prime Minister Mahmoud Abbas to try to induce Hamas and other militants to agree to a cease-fire.
As the familiar chain reaction of violence continues, the Bush Administration can only hope that the much-derailed “peace train” can be put back on the track toward Israeli-Palestinian coexistence before it disintegrates.
A so-called two-state solution remains the only long-term alternative to a continued state of siege. It is a clich to say that all sides must exercise restraint if there is to be any progress toward that solution. But yesterday's carnage is proof of what happens when settling scores takes precedence over seeking peace.